some kind of perpetual calender

[s2000]

/the task
write a program which calculates the day of the week for any date past and future, falling after 12/31/1582 to make a calendar for a specified month and year.

/the problem
I am having trouble with the code

does anyone know where I can find coding on the net or a similar project on the net that I can use as a guideline?

any help would be appreciated

thanks!
Lexi
[email protected]

[chrisjk]

You can get the day of the week like so. I tried it with the date you gave and it seemed to work okay.

Dim strDay As String
strDay = Format(#6/14/1890#, "dddd")

[Dreamlax]

I can't belive it's that simple. I thought it had something to do with this and something to do with that and VB constants and stuff. Oh well, next time I know what to do .

[s2000]

This is the whole project - very confusing - any help?


Perpetual Calendar Project


Introduction

The Gregorian calendar was introduced in 1582. You are being asked to write a program which calculates the day of the week for any date past and future, falling after 12/31/1582 to make a calendar for a specified month and year.

Overview of the Problem
a. Request the month, day, and year as numeric inputs. Use either single or multiple textboxes to capture the user’s inputs. Single text boxes make it necessary to parse the data to separate the month day and year but simplifies the user interface with the program.

b. After you determine the maximum number of days in the month, check the user’s inputs for validity. If you determine an error in the input, notify the user with an error message or frowning face symbol and allow him to correct the errant month, day or year.
The maximum number of days in each month is constant for all months except February, which is usually 28 days except leap years, when February has 29 days.

A year is said to be a leap year if all of the following conditions are met.
Any years divisible by 4 is considered a leap year, with the exception of those years divisible by 100 and not by 400. By this rule, the years 1600 and 2000 are leap years but the years 1700, 1800, and 1900 are not. If you are clever, this leap year condition can be tested with a single “If” statement. See chapter 5 of our textbook for more details on the “If” and the “Select Case”

Algorithm

Use the following algorithm to determine the day of the week for a given date.

1) Treat January and February as the 13th and 14th months of the previous year, respectively. Thus, 1-10-98 is treated as 13-10-1997. Similarly, 2-10-1998 becomes 14-10-1997.

2) Let m, d, and y denote the month, day, and year, respectively. Similarly,
2-10-1998 becomes 14-10-1997. Compute w, where

w = d + 2*m + Int((3/5)*(m +1)) + y + Int(y/4) – Int(y/100) + Int(y/400) + 2

3) The remainder of w divided by 7 denotes the day of the week, where 0 is Saturday, 1 is Sunday, 2 is Monday, and so on. Hint : See the “Mod” function described on page 126 – Comment 8 of our text.

[chrisjk]

Use the following algorithm to determine the day of the week for a given date

Do you have to use the algrothim. That would take an age to code, but the alternative is only 1 line!!

[s2000]

well the whole project is supposed to be about 100 lines.

[JamesM]

Adding validity check for valid dates:

To a project add a text box and a command button, then add code behind form.

Option Explicit

Private Sub Command1_Click()
If IsDateValid(Text1) Then
    MsgBox Format(Text1, "dddd")
Else
    MsgBox "You have Not entered a valid Date :-(."
End If
End Sub


Function IsDateValid(strDate As String) As Boolean
'stop users from entering dates Not valid according To locale settings
'e.g. If dd/mm/yy local settings Then 12/24/2000 = invalid, 24/12/2000 = valid
Dim pos As Integer
pos = InStr(1, strDate, "/")
If IsDate(strDate) Then If Left(strDate, pos) = Left(CDate(strDate), pos) Then IsDateValid = True
End Function

[JamesM]

A shortcut to leap year calculation, why reinvent the wheel:

Function IsLeapYear(ByVal sYear As String) As Boolean
    If Month(DateSerial(sYear, 2, 29)) = 2 Then IsLeapYear = True
End Function

[JamesM]

Must be bored to reinvent the wheel , here it is:

Function IsLeapYear(ByVal sYear As String) As Boolean
    If sYear Mod 400 = 0 Then
        IsLeapYear = True
    ElseIf sYear Mod 100 = 0 Then
        IsLeapYear = False
    ElseIf sYear Mod 4 = 0 Then
        IsLeapYear = True
    End If
End Function

[anoop007]

This is a QBasic program i did a long time ago (when i didn't have VB) to create a perpetual calender..
displays calender of any year..

Try to convert this somehow to VB!

On ERROR GoTo 999
Dim M$(12), D(12), day$(7)
For I = 1 To 12
Read M$(I), D(I)
Next I
For I = 1 To 7
Read day$(I)
Next I
CLS

140 Print "Super Calender v2.0"
Print "By Anoop Sankar, March 1999"
Print "To display BC years, use a negative sign"
Print
Input "Enter year,0 to stop : ", Y

If Y > 0 Then year$ = Str$(Y) + " AD" Else year$ = Str$(Abs(Y)) + " BC"
If Y = 0 Then End
yr = Int(Y / 100)
y1 = yr / 4
sy = (y1 * 6 + (yr - y1) * 5) Mod 7 + 1
If sy = 7 Then sy = 0
p1 = (Y / 100 - yr) * 100: P = Int(p1)
If p1 >= (P + .5) Then P = P + 1
nly = P / 4

While nly > 7
nly = nly - 7
Wend

sly = sy + (3 - (2 * (nly - 1)))

While sly < 0
sly = sly + 7
Wend

dfly = P Mod 4
If dfly <> 0 Then dfly = dfly + 1
ast = sly + dfly

While ast > 6
ast = ast - 7
Wend

If (Y / 4 = Int(Y / 4)) And (Y Mod 100 <> 0) Or (Y / 400 = Int(Y / 400)) Then D(2) = 29
c = ast * 10
CLS
       
        For I = 1 To 12
                If I / 2 <> Int(I / 2) Then Print TAB(37); year$: Print
                Print : Print
                Print TAB(38); M$(I): Print
                R = 0
                       
                        For J = 1 To 7
                                Print TAB(R); day$(J);
                                R = R + 10
                        Next J
                Print
                        For K = 1 To D(I)
                                Print TAB(c + 4); K;
                                c = c + 10
                                If c > 60 Then c = 0: Print
                        Next K
                If I / 2 = Int(I / 2) Then Print : Print "Press any key to continue...": Do: Loop Until INKEY$ <> "": CLS
        Next I
D(2) = 28: CLS : GoTo 140
DATA January,31,February,28,March,31,April,30,May,31,June,30,July,31,August,31
DATA September,30,October,31,November,30,December,31
DATA Sunday,Monday,Tuesday,Wednesday,Thursday,Friday,Saturday

999 BEEP: Print "Error    :"; ERR; "in line"; ERL
Do: Loop Until INKEY$ <> ""
If ERR = 6 Then Print "OVERFLOW" Else Print "UNKNOWN ERROR"
Print "CLEAN EXIT"
End